Eurofins study - Ultrashort PFAS in Swedish and Norwegian drinking water
In recent years ultrashort PFAS have attracted more and more attention. This applies specially to drinking water for which reports from Germany, The Netherlands and Switzerland among other countries have demonstrated their ubiquitous presence. This is also the case for potential water sources, as seen for Danish groundwaters. Concentrations of, in particular, trifluoroacetic acid (TFA) in precipitation has increased substantially since the 90’s and moreover there are 45 active pesticide substances approved in the EU that may degrade to TFA (see report for references). Ultrashort PFAS are characterized as having one, two or three carbon atoms and besides TFA, four other compounds are commonly considered: perfluoro propionic acid (PFPrA), trifluoromethane sulhonic acid (TFMS; triflic acid), perfluoroethane sulphonic acid (PFEtS) and perfluoropropane sulphonic acid (PFPrS). Each can have different sources e.g. TFMS can be used as an additive in lithium ion battery electrolytes.
The knowledge of ultrashort PFAS in Scandinavian drinking waters is still limited. Eurofins has carried out a project where 32 samples from 31 cities in Sweden and Norway were investigated. In addition, a set of 30 other PFAS were determined. The results showed that TFA was present in all waters in the range 70-720 ng/l (280±160 ng/l; mean ± s.d.) with the lowest value recorded for Trondheim and the highest for Visby on the island of Gotland. TFMS was also found in a number of samples (up to 1.5 ng/l), while PFPrA and PFPrS were found on one occasion at Uppsala South, a site with a known PFAS contamination. In general, the lowest TFA levels were seen in W and N Norway and the highest along the S-E Swedish coast. Overall, concentrations decreased from south to north and rose from west to east. Regarding PFAS4 the Swedish limit of 4 ng/l was exceeded at four locations and the Danish value of 2 ng/l at ten. If TFA was to be included in the “PFAS total” parameter in the drinking water directive (DWD) the sum would pass the 500 ng/l limit at two sites (Visby and Karlskrona) with other sites in S-E Sweden just below.
The work was performed on drinking (tap) waters mainly taken directly at users. To further elucidate sources and trends, studies on raw waters, water bodies (ground, surface, infiltration etc) and water treatments as well as seasonal variations would be required. Taken as a whole the results show that ultrashort PFAS are relevant in a context of DWD and for TFA also the proposed revision of the groundwater directive as being a so called non-relevant metabolite (NrM). Moreover, the compounds need to be discussed as a part of a wider group of vPvM and PMT substances. The study is going to be presented at the Flouros 2023 conference 30 Aug – 1 Sep in Idstein (DE) together with two other Eurofins contributions.
Questions on the report can be answered by Patrick van Hees (e-mail: patrickvanhees@eurofins.se)
Links and Downloads
The report can be downloaded here
Ultrashort PFAS analysis
General PFAS information